Die-casting metal



Patented Aug. 17, 1926.

UNITED STATES PATENT OFFICE.

WILLIS 1!. P1811803 AID nmnnrn A. AI'I'DEBS ON, 01' PALIIBI B-TO N. PENNSYLVANIA, Afl- SIGNOBS TO m NEW JERSEY ZINC COMPANY, 0] NEW YORK, N. Y., A CORPORA- TION OI NEW JERSEY.

Io Drawing.

This invention relates to casting alloys, and particularly to die-casting alloys having zinc as the principal wnatituent'and containing aluminum with or without copper I or other elements to give the metal the desirable and necessary characteristics.

Die-casting metals of this kind are well known and in common use and comperatively high terlsilc stren igh imlU act strength and fair ductility. These eloys are also notably free from hot short. ness and are reasonably satisfactor v -.thcrctore, as die-casting materials. The known alloys are, howevennubject to intercryetelline oxidation in the presence of warmth and moisture and are liable to swelling, warping and loss of strength when subjected to such adverse conditions. Moreover, changes occur in these alloys upon simple nging at ordinary temperatures unaccompanied by serious intercrystelline oxidation, which may result in serious detriment to the physical properties such as tensile and impact strength.

It is the object of the present invention to improve alloys such as these cast in permanent and sand molds, and particularly die-casting alloys by reducing t e tendency to inlercrystailiiie oxidntiog enrilmcha upon agin w is pmervi or proving the other p -o ies of the metal which make it suitable for die-casting purposes. Other objects and advantages of the invention will be apparent as it is better understood by reference to the following specificntion in which the preferred embodi' ments of the invention are described. 0

The invention depends upon the addition of ma esium i re atively small amounts to zinc e loye an upon the-efl'ect thereof in reducing deterioration by oxidation, and furthermore in preventing undesirable chimgesjin ph 'sical properties due to structural or equilibrium changes which tend to proceed slowly in these alloys. It has been discovered that the addition of as little as one tenth of one per cent of magnesium to an allo of zinc and aluminum containin prefer: I at least eighty-five per cent 0 zinc resu ts in a very marked improvement of the metal. On the other hand, the addition of magnesium must not exceed substantially three 'enths of one per cent because any material addition to this amount will result in serious impairment of the duc- DIB-OAS'IIN'G METAL.

Application fled lay 11, 1825. Serial 110. 88,800.

tility and casting properties of the metal.

gnesium has the same beneficial effect when added in substantially the some proportions tozinc alloys containing both copper and aluminum in amounts totalling not on more substantially then fifteen per cent.

As an example of the invention, an alloy of zinc base with aluminum in variable pro portlons betvveen one and fifteen per cent on be materially improved by the addition as of one tenth 10f one per cent of magnesium thereto. Such an a] ov has a high tensile strength and is affected much less seriously by oxidizing conditions than the same alloy without the addition of magnesium. Fur- 10 thermore, aging when unaccompanied b -serious oxidation, does not result in detrione tenth of one per cent of magnesium and the relative properties of the two metals are 86 indicated by the following table indicating tests conducted with the two alloys:

Allo No. 1 was a zinc base alloy containing 4 0 Al and 3% Cu, and allcI No. 2 was a zinc base alloy containing a A], 3%

('Ju, and 0.1% Mg.

Mlo

All No. o,

(1.31! ll, aw .6

BALM $1. m

m c ii s m I new aw m d; In

0D 0 0 ml lnlutuntadntmoepbereatlfi'llnnvmlocg. .017 .M

The alloy containing magnesium has high fluidity and lower shrinkage and is a better casting metal. its ductility is unimpaired. o

" magnesium in relatively small amounts has The same improvement by the addition of gar cent, to zinc alloys containing eightyn noted, also in connection with other more metals, such as aluminum, copper etc, alloys containing relatively large proporto produce die-casting metals hav' high tions of zinc and aluminum with other tensile stren h, good ductility and hill remetals similar to cop r. The reason for sistance to eterioration when aged in the ve per cent or more of the zinc and one or 30 the 1m rovement no cannot be fully expresence of warmth and moisture and when 35 plaine The effect apparently is to reduce a ed in ordinary atmospheres. Various the tendency tointercrystalhne oxidation c anges may be made, therefore, in the conwith the result that the alloy is stabilized stituents and" proportions thereof as used in and prevented from deterioratin in the the alloys without departi from the invenmanner common with man zinc use dietion or sacrificing any 0 the advantages 40 casting alloys contalmn a ummum. thereof.

It is to he understoo that in preparing We claim: the alloys described the zinc used should be 1. A zinc base alloy containing not less substantially pure and substantially free at than 85% zinc and 0.01 to 0.3% magnesium. least from impurities such as lead and cad- 2. A zinc-base alloy including 1.0 to 15% 46 mium which are known to cause the dealuminum and 0.01 to 0.3% magnesium. terioration of zinc base die-casting alloys 3. A zinc-base alloy including 1.0 to 15% containing aluminum. A high grade zinc, aluminum and copper,- and 0.01 to 0.3% such as the well-known Horsehead brand, magnesium. should be used, therefore and the other 4. A zinc-base alloy including approxi- 0 metals employed should likewise be free mately 4% aluminum, 3% copper, and 0.01 from impurities which are likely to have a to 0.3% magnesium.

deteriorating influence u n the alloy. In testimony whereof we atiix our signa- The invention comprelends the-addition tures. of relatively small amounts of magnesium, W. M. PEIRCE.

for example one' tenth to three tenths of one EDMUND A. ANDERSON.

The same improvement by the addition of magnesium in relatively small amounts has been noted, also in connection with other alloys containing relatively large proportions of zinc and aluminum with other metals similar to copper. The reason for the improvement noted cannot be fully explained. The effect apparently is to reduce the tendency to intercrystalline oxidation with the result that the alloy is stabilized and prevented from deteriorating in the manner common with many zinc base diecasting alloys containing aluminum.

It is to be understood that in preparing the alloys described the zinc used should be substantially pure and substantially free at least from impurities such as lead and cadmium which'are known to cause the deterioration of Zinc base die-casting alloys containing aluminum. A high grade zinc, such as the well-known Horsehead brand, should be used, therefore, and the other metals employed should likewise be free irom impurities which are likely to have a deteriorating influence upon the alloy.

per cent, to zinc alloys containing eightyve per cent or more of the zinc and one or more metals, such as aluminum, copper. etc., to produce die-casting metals having high tensile strength, good ductility and high resistance to deterioration when aged in the presence of warmth and moisture and when aged in ordinary atmospheres. Various changes may be made, therefore, in the constituents and proportions thereof as used in the alloys without departing from the invention or sacrificing any of the advantages thereof.

\Ve claim:

1. A zine base alloy containing not less than 85% zinc and 0.01 to 0.3% magnesium.

A zinc-base alloy including 1.0 to 1.55/0 aluminum and 0.01 to 0.3% magnesium.

3. A zinc-base alloy including 1.0 to 15% aluminum and copper, and 0.01 to 0.3% magnesium.

51. A zinc-base mately 4% aluminum, to 0.3% magnesium.

In testimony whereof we afiix our 'signa- 3% copper, and 0.01

The invention comprehends the addition tures.

of relatively small amounts of magnesium, \V. M. PEIRCE,

for example one tenth to three tenths of one EDMUND A. ANDERSON.

DI so LAI M E R 1,596,761.--Wil1 ia CASTING 1927, by the assignee, Hereby disclaim from those containin aluminum and copper that thealloys The New Jersey M. Peirce and Edmwnd METAL. Patent dated August A. Anderson, Palmerton, Pa. Dm 17, 1926. Disclaimer filed, May 20,

Zinc Company. the scope of claims 1, 2 and 3 all zinc-base alloys except or their equivalents, in such proportions .have such tensile strength, impact strength, ductility, fluidity,

low shrinkage and freedom from hot-shortness as make them suitable for die-casting purposes; in which alloys magnesium 1n crystalline oxidation and undesirable change [oflicial Gazette June 7, 1927.]

the percentages specified reduces inters in physical properties upon aging.

alloy including approxi- DISCLAIMER.

1,596,761.-WiZ1 is M. Peirce and Edmund A. Anderson, Pelmerton, Pa; Dm-

CASTING METAL. Patent 'dated August 17, 1926. Disclaimer filed, May 20, 1927, by the assignee, The New Jersey Zinc 0021142011 1.

Hereby disclaim from the scope of claims 1, 2 and 3 all zinc-base alloys except those containing aluminum and copper, or their equivalents, in such proportions that the' alloys .have such tensile strength, impact strength, ductility, fluidity, low shrinkage and freedom from hot-shortness as make them suitable for die-castingpurposes; in which alloys magnesium in the percentages specified reduces intercrystalline oxidation aml undesirable changes in pliysical properties upon aging.

[Ofim'al Gazette June 7,-1.9!372] 

